1. Field of the Invention
The present invention relates to an antibacterial gypsum composition for dental surgery. More particularly, the present invention relates to an antibacterial gypsum composition for dental surgery, which eliminates pathogens transferred from the mouth of a patient, so that a dentist or others participating in dental surgery can be prevented from being infected by such pathogens during work for dental surgery.
2. Description of the Prior Art
In general, calcined gypsum is hydraulic gypsum (which is curable upon the reaction with water), and thus is used as a material for making a model in various applications.
Particularly, calcined gypsum is essential to make a denture model for producing various dentures, including a total denture, a partial denture, a crown, a bridge, an inlay and an occlusion frame, mounted in the oral cavity.
In general, a denture model is obtained by the method comprising the steps of: forming a negative mold, also referred to as an impression, by using an impressing material; and pouring calcined gypsum slurry dissolved in water into the negative mold; and setting the model.
Conventional impressing materials include rubber (e.g. silicone rubber, polyether rubber and polysulfide rubber) and hydrocolloid (e.g. agar and alginate).
Materials used for a denture model are required to have a sufficient dimension precision, mechanical strength, soft surface-forming capability upon the contact with various impressing materials, easy handling property, stability with a lapse of time and processability. Also, such materials should not cause a significant foaming phenomenon.
To improve a dimension precision, JP-A 50-161492 (herein, JP-A refers to “Japanese unexamined laid-open patent application) discloses a method of inhibiting gypsum from expanding upon the setting by adding an anti-expanding agent such as a sulfate, tartrate or oxalate.
To obtain a gypsum model having a high strength, a high hardness and a soft surface, it is known that a metal sulfate and melamine-formaldehyde resin is added to a type calcined gypsum (see JP-A 62-270451).
Hydrocolloid impressing materials such as agar and alginate have a disadvantage in that a gypsum model molded from such hydrocolloid materials cannot represent a soft surface. However, a composite material formed of agar and alginate, which has been developed recently, provides the advantages of agar as well as the easy handling property and cost efficiency of alginate, and thus are widely used for clinical applications.
However, the aforementioned gypsum compositions have no antibacterial or sterilizing function. Thus, when a tooth model is formed in the oral cavity of a dental patient by using gypsum, various pathogens present in the oral cavity may be attached to the gypsum and transferred to the exterior. As a result, dental technicians fabricating gypsum models or dentists handling gypsum models may be infected with such pathogens.